1. Field of the Invention
The present invention relates to a forming method and a forming body of an air discharge channel for discharging air in liquid which is supplied to a jetting head provided in a liquid jetting apparatus such as, for example, an ink-jet printer apparatus, and further relates to assembly parts of the channel forming body.
2. Description of the Related Art
As a printer apparatus of an ink jet type which is an example of a liquid jetting apparatus, there has conventionally been known one adopting a structure in which a jetting head reciprocating while facing a recording paper is supplied with ink from ink cartridges provided in an apparatus body via flexible ink supply tubes (what is called a tube supply type). Some such printer apparatus has channels through which air growing in the middle of the ink supply channels is discharged to the outside, besides channels for supplying the ink.
For example, in an ink jet printer described in U.S. Pat. No. 7,303,271B2 (corresponding to Japanese Patent Application Laid-open No. 2005-145045), these channels are formed by heat-welding a film to a resin-molded member having a groove. Other such channels being in use are a flexible tube manufactured by extrusion molding, a channel formed by welding resin-molded members to each other by ultrasonic vibration, and the like.
However, in the channel formed by heat-welding the resin-molded member and the film as shown in U.S. Pat. No. 7,303,271B2, it is difficult to control an amount of resin melting at the time of heating to a constant value, and when part of a molten resin content enters the groove formed in the resin-molded member, there occurs variation in channel sectional area. Further, since a highly flexible material is generally used as the film, the film deforms according to a change in internal pressure, which also becomes a cause of the occurrence of the variation in channel sectional area. Then, such variation in channel sectional area causes variation in channel resistance.
Here, when it is expected that variation in channel resistance may occur in some channel, a damper for some channel with small resistance has to be increased in size, while a filter and a channel diameter for the other channels with high resistance have to be increased in size. That is, in the channel with a small resistance, a pressure change of the ink or the like flowing inside easily propagates and thus a high-performance damper mechanism is necessary in order to alleviate the pressure change, which as a result necessitates the size increase of the damper. On the other hand, in the channel with a high resistance, it is necessary to make the filter disposed in the middle large or to make the channel diameter large in advance, in order to prevent lack of the supply of the ink or the like. As described above, the variation in channel resistance necessitates the size increase of the whole apparatus.
Besides the above-described channel formed by heat-welding the film to the resin-molded member, there are some other ones used as the channel, and among these, the flexible tube formed by the extrusion molding has a limit in a radius of curvature when it is curved, and it is difficult to bend it, for example, at a right angle, which poses a limit in layout of the channel. Further, though it is possible to divide the tube into a plurality of tubes to connect them by joints, a lot of skill is required for connecting the tubes with a small channel diameter and it is also difficult to ensure airtightness of connection portions.
Further, in the channel formed by welding the resin-molded members by ultrasonic wave, the molten resin content is also likely to enter the channel, which becomes a cause of variation in channel resistance.